The transmission of an impulse is made possible first by electric signals propagating within a neuron. Then, at the end of the axon called a synapse, chemical substances called neurotransmitters get released to transmit the message. These neurotransmitters then attach to chemical receptors in the following neuron.
False like blood lymph won't flow both to and from the heart
The correct answer is: d) begins later in life
Eggs or female reproductive cells are formed well before birth in a huge number (primordial oocytes). But, the number of oocyte decreases after birth constantly (there are 2 million oocytes at birth and 40,000 of them in puberty). At menopause, no egg cells are left.
On the other hand, the first sperms are formed only from puberty, but the production of those cells never stops.
<h2>Sodium channels </h2>
Explanation:
Depolarization is a result of sodium channels opening as a result of chemical or pressure-based stimuli
- Depolarization starts when a threshold stimulus applied on a neuron via Na+ mechanically operated channels that trigger action potential
- Action potential is an efficient signaling process by which distantly located cells communicate to each other
- Depolarization of membrane potential is due to influx of Na+ via voltage gated Na+ channels
- Fast opening of voltage gated Na+ channel shifts membrane potential from -70mV to + 50mV at which voltage gated Na+ channels become inactive thus influx of Na+ abruptly stops
Answer:
The correct answers are B and C. Walter Sutton and Theodor Boveri were the first to suggest that growth of cancerous cells was a result of abnormal chromosomes.
Explanation:
The chromosomal theory of inheritance is a scientific theory that relates chromosomes with the transmission of inheritable characters. It is also called the chromosomal theory of Sutton and Boveri in honor of the two people who independently developed it in 1902, Theodor Boveri and Walter Sutton. This theory states that the alleles, the Mendelian genetic factors, are on chromosomes.
Theodor Boveri and Walter Sutton independently developed the chromosome theory in 1902, Boveri, studying embryonic development in sea urchin and Sutton in this work on meiosis in grasshopper.
Sutton and Boveri's proposition in 1902 that chromosomes are the factors of Mendelian inheritance was controversial until its demonstration in 1915 by the work of Thomas Hunt Morgan in the Drosophila melanogaster fly.
